Post Task Force Draft

ELECTROENCEPHALOGRAPHY:

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   Electroencephalography (EEG): A well-established diagnostic procedure that monitors brain wave activity using scalp electrodes and provocative maneuvers such as hyperventilation and photic strobe. Information generated includes alterations in brain wave activity such as frequency changes (non-specific) or morphologic (seizures). EEG is not generally indicated in the immediate period of emergency response, or during acute evaluation and treatment. Following initial assessment and stabilization, the individual’s course should be monitored. If during this period there is failure to improve, or the medical condition deteriorates, an EEG may be indicated to assess seizures, focal encephalopathy due to persistent effects of hemorrhage, diffuse encephalopathy due to the injury, or other complicating factors such as hydrocephalus or medications. A normal EEG does not definitively rule out a seizure disorder. If there is sufficient clinical concern that a seizure disorder may exist despite a normal EEG, then a 72 hour ambulatory EEG or inpatient video-EEG monitoring may be appropriate.
   

Quantified Electroencephalography (QEEG) (Computerized EEG): A modification of standard EEG using computerized analysis of statistical relationships between power, frequency, timing, and distribution of scalp recorded brain electrical activity. These statistically generated values are then compared to those recorded from selected control and specific populations, generally using multiple regression analysis of multiple measurements and calculated parameters.

Recent studies suggest that in the future, QEEG may become a useful tool in the retrospective diagnosis of TBI and its severity, but this application remains investigational (Arciniegas, 2011; Coburn, 2006). In moderate/severe TBI, the results of QEEG are almost always redundant when traditional electroencephalographic, neurologic, and radiologic evaluations have been obtained. QEEG is not recommended for diagnosing MTBI or moderate/severe TBI.

ELECTRODIAGNOSTIC STUDIES: Limited to EMG, nerve conduction studies, and multisensory evoked potentials including visual evoked potentials (VEP), somatosensory evoked potentials (SSEP), and brain stem auditory evoked responses (BSAER).

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   EMG and Nerve Conduction Studies: Generally accepted, well-established diagnostic procedures. These studies may be useful for individuals with brain injury and EMG associated suspected peripheral nervous system involvement. They are often used to differentiate peripheral versus central spinal cord or brain deficits. These electrodiagnostic studies are possibly complementary to other imaging procedures such as CT, MRI, and/or myelography. These studies provide useful correlative neuropathophysiologic information that is unattainable from standard radiologic studies.
   

Electroneuronography (EnoG): A well-established and generally accepted test that measures facial nerve function. This test measures the action potential of different branches of a facial nerve. It is used in individuals with TBI resulting in a facial paralysis and is key in determining the need for surgical intervention. This test is most useful within the first three weeks of facial nerve dysfunction. If the action potentials on the affected side are 90–100% less than those on the normal side, it suggests significant injury to the nerve and calls for surgical exploration. Individuals with TBI whose nerve is less than 90% decreased in function have a reasonably good outcome with observation alone.

Dynamic Electromyographies: Electrodiagnostic studies utilized to distinguish the voluntary capacity of a muscle from a spastic reaction. This aids the clinician in better planning specific rehabilitative treatment. This study is helpful in the differential diagnosis and diagnostic work-up of disordered muscle tone. This is a generally accepted procedure.

Evoked Potential Responses (EP): Generally accepted, well-established diagnostic procedures. EPs are stimulus-based central nervous system electrophysiologic responses to a stimulus, either externally generated via one or more sensory modalities, or internally generated via the processing of information. Multisensory EP studies are limited to visually evoked potentials, brain stem auditory evoked potentials, somatosensory evoked potentials and cognitive evoked potentials. In moderate/severe TBI, including the “minimal responsive or vegetative state,” there is some utility in the use of these studies for differential diagnosis, prognosis, and to determine an individual’s more specific level of neurologic functioning.

Brainstem Auditory Evoked Response (BAER): A generally accepted diagnostic procedure useful in assessing damage to the brain stem, midbrain and other neural structures that govern hearing and/or balance. It may be more useful than the Somatosensory Evoked Potential (SSEP) in MTBI. A normal test does not rule out structural damage, and the test may be abnormal in middle ear and non-traumatic disease affecting the auditory pathway. Waves one and three but particularly five, are most useful in assessing injury. While amplitude and the presence of wave are important, the latency and interwave latency are equally important. This test is often sensitive but non-specific.

Electroretinogram (ERG): A generally accepted diagnostic procedure for occult retinal trauma accompanying TBI. Most traumatic retinal pathology presents as a field deficit detected by direct examination.

Cognitive Event-Related Potential: An acceptable diagnostic procedure for moderate/severe TBI. Event-related potential provides no diagnostic information in MTBI that cannot be obtained through other diagnostic procedures and is not recommended in MTBI. It may be used when other diagnoses are suspected.

Somatosensory Evoked Potential (SSEP): A generally accepted diagnostic procedure for moderate/severe TBI. SSEP provides no information in MTBI that cannot be obtained through other diagnostic means. SSEP is not recommended in MTBI. It may be used when other diagnoses are suspected.

Visual Evoked Potential (VEP): A generally accepted diagnostic procedure. Pattern reversal monocular VEP recording may detect pathology in the anterior-posterior visual pathway from the retina to the occipital cortex. It may be indicated in the event of compromised acuity or visual field defect. The VEP may occasionally be normal in cases of severe structural damage if there is enough preserved central visual field.

Vestibular Evoked Myogenic Potentials (VEMP): Refer to Section 10.c.v.

LABORATORY TESTING: A generally accepted, well-established procedure. In MTBI, laboratory tests are rarely indicated at the time of initial evaluation unless there is suspicion of systemic illness, infection, neoplasm, drug or alcohol intoxication, endocrine dysfunction, or underlying disease. Hypopituitarism occurs in approximately 17% of MTBI cases; thus, endocrine testing is frequently appropriate (Schneider, 2007). In moderate/severe TBI, extensive lab testing will be necessary to monitor electrolyte status, organ and endocrine functions, and other physiologic processes, depending on the medications used and the severity of the injury. Any individual with TBI on medication will require laboratory testing to monitor the effects on organ function and therapeutic drug levels.

NERVE BLOCKS – Diagnostic: Generally accepted procedures involving percutaneous needle injection techniques to a specific nerve. These diagnostic blocks are typically performed with quick-acting, short duration local anesthetics such as lidocaine or bupivacaine. Temporary diagnostic nerve blocks evaluate limb ROM, dystonia, or spasticity and assist in planning subsequent more specific therapy.
VISION EVALUATION: A well-established series and combination of examination techniques and diagnostic tests To establish the diagnosis of visual disorders, it is a generally accepted practice for a qualified practitioner to provide a thorough vision evaluation. The visual evaluation measures a wide range of visual processes that involve the functional status of the eyes, the visual pathways of the brain, and the systemic health conditions that affect the eyes and visual pathways. It generates information regarding the presence or absence of refractive error, vision loss, oculomotor dysfunction, binocular vision disorder, ocular injury, and pathology. Visual evaluation may be necessary to evaluate central and peripheral nervous system disorders including central visual acuity loss, visual field loss, nystagmus, ocular motility impairment, cranial nerve palsy, ophthalmoplegia, pupillary reflex disorders, and visual perceptual disorders.

Signs and symptoms of visual dysfunction commonly include, but are not limited to, the following:

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  Signs:
  

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  Blurred vision.
  
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  Eye pain.
  
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  Foreign body sensation.
  
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  Red or irritate eyes.
  

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  Symptoms:
  
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    Loss of vision in one or both eyes.
    
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    Focusing problems.
    
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    Double vision.
    
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    Eye turn (strabismus).
    
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    Eye closure or eye cover to improve function.
    
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    Impaired depth perception.
    
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    Impaired peripheral vision
    

Other symptoms that may involve central nervous processing include:

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  Headache or eye strain with use of eyes.
  
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  Head tilt.
  
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  Dizziness with use of eyes.
  
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  Visual distortions (e.g., objects, floor, or walls appear bowed, slanted, or tipped).
  
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  Reduced visual attention or concentration for visual tasks.
  

Visual evaluation is indicated when signs or symptoms consistent with a visual problem are reported by the individual, or observed by others. Significant signs and symptoms not directly and solely attributable to other causes (e.g., cognitive, vestibular, medication, psychological) indicate the need for vision evaluation as soon as is reasonably possible post-injury. Mild signs and symptoms may be monitored for several weeks to allow for resolution or improvement.

In MTBI, self-reported photosensitivity, blurred vision, double vision and saccadic deficits are relatively common, but there is usually resolution by three months post-injury. Moderate/severe TBI patients are more likely to have binocular, pursuit and /or saccadic deficits, and visual spatial deficits, and they should have a comprehensive evaluation if these are reported (Veterans Affairs Technology Assessment Program, 2009).

A vision examination may be intermediate, extended, or comprehensive, depending on the nature of the deficits. The vision examination includes, but is not limited to the following: case history, visual acuity, refraction, color vision testing, pupillary examination, visual field by confrontation, tangent screen, automated perimetry Amsler grid testing, ocular motility examination, binocularity examination, accommodation testing, intraocular pressure testing, and anterior and posterior segment examinations. Internal examination may be needed for diagnoses such as Tersenn syndrome and retinal detachment and to rule out other related diagnoses.

Diagnostic tests include, but are not limited to, visual field testing, ultrasonography, fluorescein angiography, anterior segment and fundus photography, electrodiagnostic studies, low vision evaluation, and visual perceptual testing.

Visual Field Testing: A well-established technique to evaluate central and peripheral vision. It is indicated when a field defect is suspected by the practitioner or noted by the patient. Visual field testing beyond the basic examination should be performed using a procedure and tool that is well-established and standardized. Examples include automated perimetry and Goldmann perimetry.

Ultrasonography: A well-established diagnostic test that is indicated for evaluation of ocular or orbital pathology. It is indicated for ocular lesions that are suspected but poorly visualized due to opaque ocular media or for further evaluation of ocular or orbital pathology.

Fluorescein Angiography: A well-established diagnostic test to evaluate the retinal and choroidal circulation. It is indicated when lesions of one or both of these circulations are suspected.

Visual Perceptual Testing: Consists of functional assessments to evaluate an individual’s recognition and interpretation of visual sensory information. Visual perceptual testing is indicated for determination of the level of visual perceptual impairment and/or confirmation of suspected impairment. Perceptual areas assessed include visual memory, judgment of visual spatial relationships, visual discrimination, visual motor integration, visual figure-ground discrimination, and visual attention. Numerous tests are used for the evaluation of visual perception. Some of these tests are well-established. It is suggested that only tests with established norms be used. Visual perception testing should not be used in isolation to diagnose MTBI. Interpretation should occur in the context of assessment of other cognitive functions, including attention, memory, language and executive function. Neuropsychological assessment must be performed by a neuropsychologist, neurologist, psychiatrist, occupational therapist, or speech pathologist. In complex presentations, the full battery may be required (refer to Section E.3. Neuropsychological Assessment).

Low Vision Evaluation: Well-established and indicated in the presence of subnormal bilateral visual acuity or visual field. The goal is to provide low vision aids for distance or near vision that improves visual functioning.

Electrodiagnostic Studies: Well-established and indicated in the presence of reduced visual acuity or visual fields, ocular pathology, or suspected optic nerve or visual pathway deficit (refer to Section E.6. Electrodiagnostic Studies for further description).

Optical Coherence Tomography: An interferometric technique, usually with near-infrared wavelengths, used to evaluate the optic nerve pathway, cortical visual deficits, or retina, and may be done serially.

OTOLOGY and AUDIOMETRY: Neurotologic evaluation is a widely used and generally accepted practice in cases of hearing loss, dizziness, balance problems, facial nerve injury, and cerebrospinal fluid leak. An individual with TBI may experience these symptoms.

Audiometry: A generally accepted and well-established procedure that measures hearing. An audiologist or skilled trained technician administers the test using an audiometer. The machine presents individual frequencies to the person with TBI (typically ranging from 125–8000 Hz) at different levels of loudness (in dBHL). The individual is asked to respond to the sound at its lowest detectable intensity (threshold). Normal thresholds are from 0–25dBHL and are depicted on an audiogram. The audiologist or physician should determine the presence and type (non-organic, conductive, sensorineural, presbycusis, or mixed) of hearing loss based on the audiogram and other tests reasonably deemed necessary.

If available, obtain pre-injury baseline audiograms/audiometry studies to include a summary of past audiometric history, if known (e.g., prior hearing loss, prior tinnitus, prior vestibular problems, prior injury, etc.).

Baseline audiometry following TBI is indicated when the individual with TBI presents with hearing loss, dizziness, tinnitus, or facial nerve dysfunction.

Audiograms may be obtained in serial fashion to monitor inner ear function in response to time and treatment.

Tympanometry: A generally accepted and well-established procedure that measures middle ear air pressures. It is used to help identify the presence of tympanic membrane perforations, ossicular abnormalities, and the presence of fluid in the middle ear.

Vestibular Function Tests: The most common type of vertigo is benign positional vertigo, which usually does not require additional testing because it is diagnosed with the clinical Dix-Hallpike maneuver and treated with a variety of canalith repositioning maneuvers (CRM), such as Epley and Semont maneuvers (Fife, 2000) (refer to Section J.2.c.iv. Benign Positional Vertigo (BPV)). The following tests are used to verify the presence of vertigo and specify the origin when possible.

Electro- or Video-Nystagmography (ENG/VNG): A generally accepted and well-established procedure that measures inner ear/central balance function. The test measures eye movement responses to inner ear balance stimulation making use of the vestibulo-ocular reflex. There are several components to the ENG/VNG. They include oculomotor testing, positional and positioning nystagmus testing and caloric testing. This series of tests may identify peripheral and central abnormalities, abnormalities in oculomotor function, positional nystagmus, and unilateral and bilateral vestibular dysfunction. The ENG/VNG can be helpful in identifying the affected ear. This test is often used in individuals with TBI complaining of dizziness or dysequilibrium and may help diagnose conditions such as labyrinthine concussion, vestibular hypofunction, and central vertigo. It is often used in conjunction with other tests such as the audiogram and clinical history to help arrive at a diagnosis.

Rotary Chair Testing: A generally accepted and well-established test that evaluates the ocular responses of the inner ear to rotation. It is used to identify the extent of bilateral vestibular loss and is more accurate than VNG caloric tests for this purpose. It is also useful in assessing the ability of vision to compensate for vestibular impairments and so provides prognostic information regarding recovery.

Computerized Dynamic Platform Posturography: A generally accepted and well-established test that assesses the contributions of vision, somatosensation, and the inner ear to balance control. It separately evaluates the role of lower extremity motor control to balance. It can be used to determine whether a vestibular lesion is present, but it does not localize the lesion. The purpose of this procedure is to identify the integral components of a functional balance deficit that may help in treatment planning. This technique also may be useful in monitoring neurologic recovery in individuals with TBI and balance deficits. These functional methods of evaluation are considered generally accepted practices in the evaluation of persistent vestibular and balance deficits that may require specific treatment and remediation strategies. Non-physiologic findings on this exam can result from either symptom exaggeration, anxiety, psychiatric disorders, atypical results, or malingering and should not be interpreted as malingering without other evidence. One study demonstrated positive VNG testing in a number of cases where dynamic posturography was non-physiologic (Larrosa, 2012).

Electrocochleography (ECoG): A well-established and generally accepted procedure that tests endolymphatic fluid pressures indirectly. It identifies the affected ear in cases of post-traumatic endolymphatic hydrops and post-traumatic perilymphatic fistula.

The inner ear has two fluid chambers—the perilymphatic and the endolymphatic. After TBI, it is not uncommon for patients to develop an increase in the endolymphatic fluid pressure; this condition is called hydrops. When the endolymphatic pressures are abnormally high, the inner ear membranes distend, and the ear malfunctions. Symptoms include hearing loss, dizziness that is sporadic, tinnitus, aural fullness, and sensitivity to sound.

The ECoG is a test that uses evoked potentials. The patient listens to a series of clicks. Monitors, including one sitting on the tympanic membrane, measure three potentials: the cochlear microphonic, the summating potential (SP), and the action potential (AP). An increase in the ratio of the summating potential of the action potential (SP/AP) suggests the presence of hydrops or perilymphatic fistula. The test varies in sensitivity and specificity. Diagnosis of endolymphatic hydrops requires a characteristic clinical picture with progressive hearing loss, fluctuating hearing, and recurrent vertigo episodes lasting for hours. See J.2.c.i Progressive Vestibulopathy with or without Hearing Loss. Diagnosis should not be based solely on an abnormal ECoG test result in the absence of these clinical features

Vestibular Evoked Myogenic Potentials (VEMP): A generally accepted test that evaluates the function of the saccule, one of the gravity-sensing organs of the inner ear. It is the only objective test of these organs. It is a form of auditory evoked response and is measured using the ABR and EMG equipment. A loud sound stimulus is introduced into the ear, and a vestibulo-colic reflex response from the saccule is recorded as a brief relaxation of the ipsilateral sternocleidomastoid muscle by EMG. A characteristic wave form is recorded for each ear that is analyzed for presence or absence, threshold, amplitude, and latency. Absence of a response in persons under age 60 suggests saccular damage. Reduced thresholds are indicative of semicircular canal dehiscence

Other Clinical Referrals: The treating physician may often refer individuals with TBI who have balance problems to other clinicians with appropriate training in balance to assist in their assessment. The referrals may include, but are not restricted to, neuro-ophthamology, optometry, physical therapy, occupational therapy, and chiropractic therapy. There should be a coordinated approach between these disciplines and the physician specialist in the individual’s treatment.

SWALLOWING EVALUATION: Swallowing impairment or dysphagia may be due to neurologic, structural, or cognitive deficits and may result from head trauma. Dysphagia may result in aspiration, airway obstruction, pneumonia, inadequate nutrition, dehydration, weight loss, failure to thrive, and death.

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   Clinical Assessment:
   

Clinical Bedside Assessment: This generally accepted clinical examination of oral-pharyngeal swallow function consists of pertinent medical history, examination of function of the jaw, lip, tongue, soft palate, oral sensitivity, function of pharynx and larynx, observation of dry swallow(s) and, if appropriate, with various food/liquid consistencies, ability to follow directions and discipline his/her own behaviors. If pharyngeal dysfunction or aspiration is suspected, an instrumental assessment may be indicated.

Modified Evans Blue-Dye Test (MEBDT): A variation of the clinical bedside assessment used to detect the presence or absence of aspiration in an individual with tracheostomy. This procedure uses blue dye (FC&C Blue No. 1), or methylene blue placed on the tongue, or into liquids, ice chips, or food items. Aspiration is assumed if tracheal suctioning reveals blue-tinged secretions. The MEBDT has not been found reliable in identifying individuals who aspirated trace amounts (less than 10% of the bolus). Recognizing the limitations and risks of MEBDT, it is a common and practical means of screening individuals to determine readiness for cuff deflation or further swallowing evaluation.